The present invention relates in general to an apparatus for mixing and dispensing of synthetic foams, and more particularly, to a cleaning assembly for such apparatus which is adapted for intermittently removing accumulations of dispensed synthetic foam from the face of such apparatus in a region particularly overlying the discharge opening thereof.
As is well-known to those skilled in the art, the preparation of many synthetic foams, such as polyurethane foams, requires uniform mixing of liquid organic resins with polyisocyanates. In this regard, it is often desirable to dispense the polyisocyanate resin mixture into a receptacle, such as a package and the like, before it is reacted to form the polyurethane foam, particularly, when attempting to build up a foam structure around some object as in packaging. One particular problem with the handling of polyurethane foam material is that the organic resin and polyisocyanate tend to react relatively rapidly, and can accumulate over the external surface portions of the dispensing apparatus. The accumulated foam is then most difficult to remove. This problem of rapid setting of the polyurethane foam reactants is particularly critical when the dispensing apparatus is used intermittently.
Often, it is desirable to incorporate the dispensing apparatus in an automatic system for packaging objects. In this regard, the dispensing apparatus is located at one or more work stations overlying a conveyor belt and positioned in a vertical downwardly facing direction. Objects to be packaged are indexed along the conveyor belt by a control system and subsequently stopped at each work station underlying the dispensing apparatus. The control system activates the dispensing apparatus which fills the recepticle containing the object with polyurethane foam so as to incapsulate the object. Due to the vertical downwardly facing orientation of the dispensing apparatus and its intermittent use, the exterior surface of the dispensing apparatus is susceptible to accumulations of the polyurethane foam. In particular, the foam can accumulate on the face of the dispensing apparatus such that the discharge opening becomes partially blocked causing sputtering or complete failure of the dispensing apparatus. Once this condition has occurred, the dispensing apparatus must be cleaned prior to continued operation.
It is contemplated that the cleaning of the discharge opening of the dispensing apparatus can be accomplished by a variety of techniques. For example, mechanical wiping equipment can be installed at each work station for intermittently cleaning the face and discharge opening of the dispensing apparatus. However, such mechanical wiping equipment would generally be expensive to construct and require slowing down of the packaging operation to provide sufficient time for the wiping operation to be completed before continued use of the dispensing apparatus. In addition, the dispensing apparatus may be placed in a holster having a suitable solvent for the polyurethane foam between dispensing operations. However, the use of the holster is not suitable for use with an automatic system where the dispensing apparatus must be secured at a given work station for continuous intermittent use.
Accordingly, it can be appreciated that there is a need for a cleaning assembly adapted for use with a dispensing apparatus which is operative to intermittently remove accumulated foam from the discharge opening of the dispensing apparatus which would otherwise partially or completely prevent the satisfactory operation of the dispensing apparatus such as in an automatic foam dispensing system.